So I think, unless you have some damning statement I haven't seen, you need to give the director the benefit of the doubt. If you're not comfortable with Johnny being black for some non-racist reason, please share.
Since it sounds like you are calling me a racist, I will say it has nothing to do with race. It has to do with how the characters were created. I would have the same problem if they cast a white guy to play black panther or a white woman for storm. Not accurate to the original comics.